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hyperv/vmbus: Nuke unnecessary critical sections.

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MFC after:	1 week
Sponsored by:	Microsoft
Differential Revision:	https://reviews.freebsd.org/D8906
This commit is contained in:
Sepherosa Ziehau 2016-12-28 03:07:58 +00:00
parent a0e41d3784
commit 69d2eb82d7
3 changed files with 12 additions and 14 deletions
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4
sys/dev/hyperv/vmbus/vmbus.c
View File

@ -1393,7 +1393,7 @@ cleanup:
vmbus_xact_ctx_destroy(sc->vmbus_xc);
sc->vmbus_xc = NULL;
}
free(sc->vmbus_chmap, M_DEVBUF);
free(__DEVOLATILE(void *, sc->vmbus_chmap), M_DEVBUF);
mtx_destroy(&sc->vmbus_prichan_lock);
mtx_destroy(&sc->vmbus_chan_lock);
@ -1480,7 +1480,7 @@ vmbus_detach(device_t dev)
sc->vmbus_xc = NULL;
}
free(sc->vmbus_chmap, M_DEVBUF);
free(__DEVOLATILE(void *, sc->vmbus_chmap), M_DEVBUF);
mtx_destroy(&sc->vmbus_prichan_lock);
mtx_destroy(&sc->vmbus_chan_lock);

20
sys/dev/hyperv/vmbus/vmbus_chan.c
View File

@ -775,9 +775,7 @@ vmbus_chan_clrchmap_task(void *xchan, int pending __unused)
{
struct vmbus_channel *chan = xchan;
critical_enter();
chan->ch_vmbus->vmbus_chmap[chan->ch_id] = NULL;
critical_exit();
}
static void
@ -1308,15 +1306,17 @@ vmbus_chan_pollcfg_task(void *xarg, int pending __unused)
chan->ch_poll_flags = poll_flags;
/*
* Disable interrupt from the RX bufring (TX bufring does not
* generate interrupt to VM), and disconnect this channel from
* the channel map to make sure that ISR can not enqueue this
* channel task anymore.
* Disconnect this channel from the channel map to make sure that
* the RX bufring interrupt enabling bit can not be touched, and
* ISR can not enqueue this channel task anymore. THEN, disable
* interrupt from the RX bufring (TX bufring does not generate
* interrupt to VM).
*
* NOTE: order is critical.
*/
critical_enter();
vmbus_rxbr_intr_mask(&chan->ch_rxbr);
chan->ch_vmbus->vmbus_chmap[chan->ch_id] = NULL;
critical_exit();
__compiler_membar();
vmbus_rxbr_intr_mask(&chan->ch_rxbr);
/*
* NOTE:
@ -1380,11 +1380,9 @@ vmbus_chan_polldis_task(void *xchan, int pending __unused)
* Plug this channel back to the channel map and unmask
* the RX bufring interrupt.
*/
critical_enter();
chan->ch_vmbus->vmbus_chmap[chan->ch_id] = chan;
__compiler_membar();
vmbus_rxbr_intr_unmask(&chan->ch_rxbr);
critical_exit();
/*
* Kick start the interrupt task, just in case unmasking

2
sys/dev/hyperv/vmbus/vmbus_var.h
View File

@ -93,7 +93,7 @@ struct vmbus_softc {
u_long *vmbus_rx_evtflags;
/* compat evtflgs from host */
struct vmbus_channel **vmbus_chmap;
struct vmbus_channel *volatile *vmbus_chmap;
struct vmbus_xact_ctx *vmbus_xc;
struct vmbus_pcpu_data vmbus_pcpu[MAXCPU];